Systems and methods for anchoring medical devices

ABSTRACT

Some embodiments of a medical device anchor system include an anchor device that secures a medical instrument (such as a catheter or the like) in place relative to a skin penetration point using subcutaneous anchors. In some implementations, the anchor device can be installed using a technique in which the subcutaneous anchors undergo relatively little or no flexing when being inserted through the skin into the subcutaneous region between the skin and underlying muscle tissue which may be occupied by fatty tissue.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 13/705,651filed on Dec. 5, 2012 by Rosenberg et al., which is a continuation ofU.S. patent application Ser. No. 12/893,783 filed on Sep. 29, 2010 byRosenberg et al., the entire contents of which are incorporated hereinby reference.

TECHNICAL FIELD

This document relates to a system and method for securing the positionof a catheter or another medical instrument, for example, at a skinopening.

BACKGROUND

Venous, arterial, and body fluid catheters are commonly used byphysicians. For example, such catheters may be used to gain access tothe vascular system for dialysis, for introducing pharmaceutical agents,for nutrition or fluids, for hemodynamic monitoring, and for blooddraws. Alternatively, catheters can be used for drainage of fluidcollections and to treat infection. Following introduction into thepatient, the catheter is secured to the patient. In some instances, thecatheter is commonly secured to the patient using an adhesive tape onthe skin or by suturing a catheter hub to the patient's skin. In othercircumstances, the catheter may be secured to the patient using asubcutaneous anchor mechanism (such as an anchor sleeve equipped withanchors that are deployed using an external actuator handle or aseparate delivery device).

SUMMARY

Some embodiments of a medical device anchor system include an anchordevice that secures a medical instrument (such as a catheter or thelike) in place relative to a skin penetration point using subcutaneousanchors that are readily inserted without the use of a deploymentactuator. In some implementations, the anchor device can be installedusing a technique in which the subcutaneous anchors undergo relativelylittle or no flexing when being inserted through the skin into thesubcutaneous region (e.g., the region immediately under the skin andbetween the skin and underlying muscle tissue which may be occupied byfatty tissue). As such, the subcutaneous anchors of the anchor devicemay be inserted through the skin penetration point that is alreadyoccupied by the medical instrument while in a generally non-stressed ornon-flexed shape. According to certain implementations of theinstallation technique, the subcutaneous anchors can also be shifted toa different orientation after installation into the subcutaneous region,yet the subcutaneous anchors may continue to be maintained in generallythe same shape as during insertion through the skin penetration point.Accordingly, the subcutaneous anchors of the anchor device can beinstalled through the skin and into the subcutaneous region using atechnique that reduces or eliminates flexing of the subcutaneousanchors, thereby permitting the use of more rigid materials forsubcutaneous anchors (e.g., comprising materials without superelasticcharacteristics).

In particular embodiments, the anchor device may have a foldableconfiguration that facilitates both installation and removal of thesubcutaneous anchors in a manner that reduces trauma to surroundingtissue near the skin penetration point. For example, the anchor devicecan be retained in a folded condition during installation of thesubcutaneous anchors through the skin penetration point while each ofthe subcutaneous anchor tines has a first curved shape (e.g., agenerally non-stressed or non-flexed shape). Also, the anchor device canbe adjusted to a non-folded condition after installation of thesubcutaneous anchors into the subcutaneous region, and each of theanchors tines can have generally the same first shape after the deviceis adjusted to the non-folded condition. The action of adjusting theanchor device to the non-folded condition can cause the subcutaneousanchors to shift relative to one another so that the subcutaneousanchors extend outwardly away from one another, yet may each maintainthe first curved shape (e.g., generally non-stressed or non-flexedshape). During removal, the anchor device can be adjusted again to thefolded condition so that the subcutaneous anchors are positionedside-by-side and extend generally in the same direction while also eachmaintaining generally the same first curved shape. In thesecircumstances, the subcutaneous anchors can be contemporaneouslyinstalled and removed from the skin penetration point in a manner thatreduces the likelihood of damage to the tissue surrounding the skinpenetration point while also reducing or eliminating flexing of thesubcutaneous anchors.

Some embodiments of a method of using a medical anchor system mayinclude the step of advancing an anchor device toward a skin penetrationpoint while the anchor device is in a folded condition so that aplurality of subcutaneous tines of the anchor device are generallyadjacent to each other and oriented to extend in substantially the samedirection. The method may also include inserting the subcutaneous tinesthrough the skin penetration point and into a subcutaneous regionadjacent to an underside of a skin layer while the anchor device is inthe folded condition. Each of the subcutaneous tines may have a curvedshape which terminates at a tip of a free end during insertion throughthe skin penetration point. The method may further include adjusting theanchor device to a non-folded condition after the subcutaneous tines areinserted into the subcutaneous layer so that subcutaneous tines are inan anchored position in which the free ends of the subcutaneous tinesextend generally away from one another. Also, the method may includesecuring a medical instrument to the anchor device after thesubcutaneous tines are adjusted to the anchored position in thesubcutaneous region.

These and other embodiments may provide one or more of the followingadvantages. First, some embodiments of an anchor system can retain amedical instrument in a desired position relative to a skin penetrationpoint without necessarily requiring sutures or skin adhesives. Second,in some embodiments, the anchor device can be installed in accordancewith a technique that reduces or eliminates the need to shift thesubcutaneous anchors tines to or from a flexed or stressedconfiguration. As such, the anchor tines need not undergo substantialflexing during installation or removal. Third, in some embodiments thesubcutaneous anchor tines need not have superelastic characteristics dueto the installation and removal technique, so the subcutaneous anchortines can comprise a generally less costly material (such as stainlesssteel or biocompatible polymers) rather than more costly materialsrequired for superelastic flexing. Fourth, the subcutaneous anchors canbe positioned distally of the retention portion that that readily mateswith a medical instrument (such as a catheter), thereby enabling thesubcutaneous anchors tines to be secured in the subcutaneous regionunder the skin while the catheter or other medical device is retainedexternally from the skin. Fifth, in some embodiments, the anchor devicemay be adjusted between a folded configuration and a non-foldedconfiguration so that the subcutaneous anchors are arranged side-by-sideand extend in generally the same direction during both installationthrough and removal from the skin penetration point. In thesecircumstances, the subcutaneous anchors may be readily installed andremoved from the skin penetration without the need for a separateexternal actuator or delivery device.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an anchor device with a portion of thedevice located in a subcutaneous region, in accordance with someembodiments.

FIGS. 2-3 are top and front views, respectively, of the anchor device ofFIG. 1 with the medical device retention portion in an open and deployedconfiguration.

FIGS. 4-7 are perspective views of a method of using an anchor system,including the anchor device of FIG. 1, for use in securing the positionof a medical instrument.

FIG. 8 is a perspective view of an anchor device for use in the methodof FIGS. 4-7, including a mechanism for retaining the anchor device in afolded condition in accordance with some embodiments.

FIG. 9 is a perspective view of an anchor device for use in the methodof FIGS. 4-7, including another mechanism for retaining the anchordevice in a folded condition in accordance with other embodiments.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1, some embodiments of a medical device anchor system10 include an anchor device 100 that releasably retains a medicalinstrument 20 (e.g., depicted as a catheter in this embodiment) in anoperative position relative to a portion of skin 30 (e.g., relative to askin penetration point 32). The anchor device 100 may include a base 110and a cap assembly 130. The base 110 may include a retainer body 111 andone or more anchors 140 a-b that extend distally from the retainer body111 for deployment in a subcutaneous layer 34. As described in moredetail below in connection with FIGS. 4-7, the anchor device can beinstalled into a skin penetration point 32 in accordance with atechnique that reduces or eliminates the need to shift subcutaneousanchors tines 145 a-b of the anchors 140 a-b to or from a flexed orstressed configuration. As such, the anchor tines need not undergosubstantial flexing during installation or removal. In thesecircumstances, the subcutaneous anchors may be both installed andremoved from the skin penetration advantageously without the need for anexternal actuator handle or delivery device to deploy the subcutaneoustines.

As shown in FIG. 1, after installation of the subcutaneous anchor tines145 a-b into the subcutaneous layer 34, the base 110 can receive themedical instrument 20, and the cap assembly 130 can be removably coupledto the base 110 to secure the medical instrument 20 in a generally fixedposition relative to the base 110. The base 110 and the cap assembly 130can include gripping members 120 and 135, respectively (refer also toFIGS. 2-3). When the cap assembly 130 is coupled to the base 110, thegripping members 120 and 135 can releasably engage with an outer surfaceof the medical instrument 20. The medical instrument 20 can extend fromthe gripping members 120 and 135 and through a skin penetration point 32in a patient's skin 30, while the retainer body 111 and the grippingmembers 120 and 135 remain outside of the skin 30. IN some embodiments,the skin penetration point 32 may be defined by a small incision, apuncture, or the like.

As described in more detail below, the anchor device 100 can secure thecatheter 20 in the operative position relative to the penetration point32 without necessarily requiring sutures or adhesive tapes bonded to theskin. For example, the base 110 can include the one or more anchors 140a and 140 b that extend distally from the retainer body 111 so as topenetrate through the same skin opening as the medical instrument 20.The anchors 140 a and 140 b can include the tines 145 a and 145 b that,after insertion, reside in the subcutaneous region 34 so as to securethe position of the anchor device 100—and the medical instrument 20retained therein—relative to the penetration point 32.

Referring now to FIGS. 1-3, in some embodiments, the medical instrument20 can include a catheter to be inserted through the penetration point32 of the skin 30 as part of a medical procedure. For example, in theembodiment depicted in FIG. 1, a central venous catheter 20 can beinserted into a percutaneous opening surgically formed in the skin(e.g., penetration point 32), to the underside of the skin 30, and intoa vein 40 to provide vascular access for delivering medications orminimally invasive devices into a patient. After placement of thecatheter 20, the base 110 of the anchor device 100 can approach thepenetration point 32 such that the free ends of the tines 145 a-b arecontemporaneously inserted through the penetration point 32 while thetines 145 a-b are in a generally side-by-side condition (refer, forexample, to FIGS. 4-5). As the anchor device 100 is inserted through thepenetration point 32, the tines 145 a-b are maintained in a generallynon-stressed configuration (e.g., a first shape or a steady-state shape)while passing through the penetration point 32 in a manner that reducesthe likelihood of trauma to the surrounding skin tissue. As the tines145 a-b are collectively advanced through the penetration point 32, thefree ends of the tines 145 a-b are moved beneath the dermal skin layers36 of the skin 30. When the tines 145 a-b reach the subcutaneous region34, the tines 145 a-b can be shifted relative to one another so that thetines 145 a-b extend outwardly away from one another while each tine 145a-b retains the generally non-stressed configuration (e.g., the firstshape or the steady-state shape). Thus, as described in more detailbelow in connection with FIGS. 4-7, the anchor device 100 can beinstalled in accordance with a technique that reduces or eliminates theneed to shift the subcutaneous anchors tines 145 a-b to or from a flexedor stressed configuration during the passage through the skinpenetration point. As such, the subcutaneous anchors tines 145 a-b neednot undergo substantial flexing during installation or removal, and insome embodiments, the subcutaneous anchors tines 145 a-b can comprise agenerally less costly material (such as stainless steel or biocompatiblepolymers) rather than more costly materials required for superelasticflexing.

Referring now to FIG. 2, each of the anchors 140 a-b may be designedsuch that the tines 145 a-b has a first shape with a convex curvaturethat abuts against the underside of the dermal layers 36 in a mannerthat reduces the likelihood of the tine tips 146 puncturing theunderside of the dermal layers 36. Preferably, the tine tips 146 arerounded or otherwise non-sharp so as to further protect the underside ofthe dermal layers. When the tines 145 a-b of the anchors 140 a-b aredeployed in the subcutaneous region 34, the cap assembly 130 can beremovably coupled to the base 110 (refer, for example to FIG. 7),compressing the gripping portions 120 and 135 onto the medicalinstrument 20 and causing the gripping portions 120 and 135 toreleasably engage with an outer surface of the medical instrument 20. Inthis way, the anchor device 100 can be secured to the patient withoutthe retainer body 111 penetrating though the skin 30 of the patient andwithout necessarily requiring sutures or adhesive tapes bonded to theskin 30.

Referring now to FIGS. 2-3, some embodiments of the anchor device 100can include structures designed to mate with portions of the medicalinstrument 20 to be retained by the anchor device 100. The anchor device100 can include the gripping members 120 and 135 used to secure thecatheter 20 (or other medical instrument) relative to the skinpenetration point 32. For example, after the catheter 20 is deliveredinto the targeted vein 40 (or other bodily lumen) and after the tines145 a-b are anchored in the subcutaneous region 34, the cap assembly 130can be removably coupled to the base 110, compressing the grippingmembers 120 and 135 to temporarily engage with the outer surface of thecatheter 20. In this way, the anchor device 100 can be transitioned fromthe open configuration (shown in FIG. 2-3) to the closed configuration(shown in FIG. 1) to thereby secure the catheter 20 with the grippingmembers 120 and 135. As described in more detail below, the retainerbody 111 can include locking tabs 112 that can pass through openings 132in the cap 131 and positively engage at least a portion of perimeters134 of the openings 132, thereby removably coupling the cap assembly 130to the base 110.

Still referring to FIGS. 2-3, the anchor device 100 can include featuresthat facilitate separation from the catheter 20, which can permit thecatheter 20 and anchor device 100 to be removed from the skin 30independently of each other. For example, the tabs 112 may be disengagedfrom the cap assembly 130 to decouple the cap assembly 130 from the base110. Once the cap assembly 130 is removed, the gripping members 120 and135 can release from the catheter 20, thereby allowing the catheter 20to be moved relative to the anchor device 100. As such, the catheter 20can be moved independently from the anchor device 100, for example, towithdraw the catheter 20 from the patient while at least a portion ofthe anchor device 100 remains secured to the skin 30.

Some embodiments of the anchor device 100 can include structuresconfigured to mate with portions of the medical instrument 20 to beretained by the anchor device 100. For example, when the anchor deviceis in the closed configuration (as depicted in FIG. 1), the grippingmembers 120 and 135 can define a channel 122 (illustrated in FIG. 2)that extends longitudinally from the proximal portion 103 of the anchordevice 100 toward the anchors 140 a-b. The channel 122 can be configuredto complement an outer surface of the catheter 20 or other medicalinstrument to be anchored by the device 100. For example, duringinstallation of the anchor device 100, the anchors 140 a-b are directedtoward the penetration point 32 through which the catheter 20 passes.When the tines 145 a-b are anchored in the subcutaneous region 34, thecap assembly 130 can be removably coupled to the base 110, whichtransitions the anchor device 100 to the closed configuration. As such,the catheter 20 can extend though the channel 122 when the subcutaneoustines 145 a-b are arranged in the region immediately under the skin 30.

In some embodiments, particular features of the anchor device 100 canremovably couple the base 110 to the cap assembly 130. In the exampledepicted in FIG. 3, the cap assembly 130 can be moved toward the base110 (e.g., in the direction depicted by arrow 106) to direct the tabs112 toward to the openings 132. When the diagonal faces of the tabs 112contact the perimeters 134, the tabs 112 are stressed such that the tips115 of the tabs 112 move closer to each other. When the face 135 movesbeyond the engagement fingers 116, the tabs 112 can outwardly towardtheir unstressed positions to releasably engage the perimeters 134. Whenin this closed configuration, the cap assembly 130 and base 110 canapply a compressive force from the gripping members 120 and 135 to thecatheter 20 in the channel 122, thereby applying a frictional holdingforce to the catheter 20 or medical instrument therein.

In some embodiments, the holding force that secures the catheter 20 tothe anchor device 100 can be released by separating the cap assembly 130from the base 110. The cap assembly 130 can be separated from the base110 by disengaging the locking tabs 112 from the cap assembly 130. Forexample, the base 110 can be separated from the cap assembly 130 byapplying pressure to the locking tabs 112 to move the tips 115 closer toeach other. When the engagement portions 116 of the tabs 112 move insidethe openings 132 in the cap 131, the retainer portions 120 and 135 forcethe cap assembly 130 away from the base 110 and the cap assembly 130becomes decoupled from the base 110, thus transitioning the anchordevice 100 to the open configuration (FIGS. 2-3). When the anchor device100 is in the open configuration (e.g., with the cap 130 removed), thecatheter 20 can be moved relative to the anchor device 100.

Referring now to FIGS. 4-7, the anchor device 100 can be installed usinga technique in which the subcutaneous anchor tines 145 a-b undergorelatively little or no flexing when being inserted through the skinpenetration point 32 into the subcutaneous layer 32 between the skin 30and the underlying muscle tissue. As such, the subcutaneous anchorstines 145 a-b can be inserted through the skin penetration point 32 thatis already occupied by the catheter 20 while each tine 145 a-b ismaintained in a generally non-stressed or non-flexed shape. Also, asdescribed in FIGS. 6-7, the subcutaneous anchors tines 145 a-b can alsobe shifted to a different orientation after installation into thesubcutaneous region 34, yet the tines 145 a-b may continue to bemaintained in the generally non-stressed or non-flexed shape.Accordingly, the subcutaneous anchors of the anchor device can beinstalled through the skin and into the subcutaneous region using atechnique that reduces or eliminates flexing of the subcutaneousanchors, thereby permitting the use of more rigid materials forsubcutaneous anchors (e.g., comprising materials without superelasticcharacteristics).

In this embodiment, the anchor device 100 may include features thatallow the individual anchors 140 a-b to be moved relative to each otherso as to facilitate both insertion and removal of the anchor device 100through the skin penetration point. For example, the anchor device 100may have a foldable configuration in which a first portion of the base110 is pivotably coupled to a second portion of the base 110. The anchordevice 100 can include a left portion 101 a and a right portion 101 b(refer to FIG. 2), which can be flexibly pivoted with respect to eachother along a fold line 113 (refer to FIG. 2) extending longitudinallythrough the retainer body 111. The left portion 101 a can include a leftretainer body portion 114 a (refer to FIG. 2) fixedly coupled to theanchor 140 a, and the right portion 101 b can include a right retainerbody portion 114 b (refer to FIG. 2) fixedly coupled to the anchor 140b. Thus, as shown in FIG. 4, when the left and right retainer bodyportions 114 a and 114 b are pivoted about the fold line 113, the twoanchors 140 a-b likewise pivot relative to one another. This process cancause the anchor device to transition from a folded condition (shown inFIGS. 4-5), in which the tines 145 a-b are generally adjacent to eachother and oriented to extend in substantially the same direction, to anon-folded condition (shown in FIGS. 6-7 and in FIG. 1), in which thetines 145 a-b extend generally away from one another. In the depictedembodiment, the tines 145 a-b can be rotated about 75-degrees to about105-degrees, and preferably about 90-degrees, during the transitionbetween the folded condition and the non-folded condition. As describedin more detail below, the anchor device 100 can be arranged in thefolded condition during both insertion and removal of the subcutaneoustines 145 a-b so as to reduce the likelihood of the tines 145 a-bcausing damage to the skin 30.

In particular embodiments, a method of using the medical anchor system(including the anchor device 100) may include an advantageous insertiontechnique. As shown in FIG. 4, the method may include a step ofinserting a medical instrument (such as catheter 20) through the skinpenetration point 32 (e.g., a puncture opening or incision) of thepatient's skin 30. One example of the catheter 20 being inserted throughthe penetration point 32 is depicted in FIG. 4. In this embodiment, thecatheter 20 may include a central venous catheter that extends from alocation external to the skin 30, through the skin penetration point 32,and into a blood vessel 40 (FIG. 1) underlying the skin 30 andsubcutaneous layer 34.

As shown in FIG. 4, after the catheter 20 or other medical instrument isinserted so that it occupies the skin penetration point 32, the methodmay include the step of advancing the anchor device 100 toward the skinpenetration point 32 while in the folded condition. As previouslydescribed, when the base 110 of the anchor device 100 is in the foldedcondition, the subcutaneous tines 145 a-b are generally adjacent to eachother and oriented to extend in substantially the same direction. Assuch, the tips 146 of the subcutaneous tines 145 a-b can located in aside-by-side position so that the tips 146 can be contemporaneouslyadvanced to the skin penetration point 32 that is already occupied bythe catheter 20 to be anchored. As described in more detail below, theanchor device 100 may be equipped with a clip device 160 or 170 (FIG. 8)or a snap connector 180 a-b (FIG. 9) that retains the base 110 in thefolded condition prior to insertion of the subcutaneous tines 145 a-b.

As shown in FIG. 5, the method may also include the step of insertingthe subcutaneous tines 145 a-b through the skin penetration point 32while the base 110 of the anchor device 100 is in the folded condition.In such circumstances, the tips 146 of the subcutaneous tines 145 a-bare generally adjacent to each other so that they can be the firstportion of the subcutaneous tines 145 a-b to initially advance throughthe skin penetration point 32 and into the subcutaneous layer 34.Because the subcutaneous tines 145 a-b are generally adjacent to eachother and oriented to extend in substantially the same direction, thesubcutaneous tines 145 a-b can be simultaneously inserted while beingmaintained in a non-stressed configuration. For example, thesubcutaneous tines 145 a-b are not necessarily forced into a flexed orstressed configuration by another component of the anchor system 10during insertion of the subcutaneous tines 145 a-b. In particularembodiments, the subcutaneous tines 145 a-b are inserted through theskin penetration point 32 while the user grasps the base 110 of theanchor device 100 and applies a downward force until the convexly curvedbody portions of the subcutaneous tines 145 a-b are positioned below thesurface of the skin 30 (while the remainder of the anchor device 100resides external to the skin 30).

As shown in FIG. 6, the method may also include adjusting the anchordevice 100 to the non-folded condition after the subcutaneous tines 145a-b are inserted into the subcutaneous layer 34. As previouslydescribed, the free ends of the subcutaneous tines 145 a-b extendgenerally away from one another when the anchor device 100 is shifted tothe non-folded condition. In such circumstances, the subcutaneous tines145 a-b are oriented in an anchored position in the subcutaneous layer34 so as to anchor the retention portion 111 relative to the skinpenetration point 32 that is occupied by the catheter 20. When in theanchored position, each of the tines 145 a-b can be maintained atgenerally the same shape as when they were inserted through the skinpenetration point (e.g., the generally non-stressed shape in which inwhich no other components of the anchor system 10 are forcing the tines145 a-b to flex). Accordingly, the convex curvature of the tines 145 a-babuts against the underside of the skin 30 in a manner that reduces thelikelihood of the tine tips 146 puncturing the underside of the dermallayers 36. As previously described, the tine tips 146 are rounded orotherwise non-sharp so as to further protect the underside of the dermallayers.

As shown in FIG. 7, the method may also include securing the catheter 20to the anchor device 100 after the subcutaneous tines 145 a-b areanchored in the subcutaneous layer 34. In this embodiment, the portionof the catheter 20 that is external to the skin 30 can be positioned inthe channel 122 (FIG. 2) of the base 110. The cap assembly 130 can beremovably coupled to the base 110 (refer, for example to FIG. 1) so thatthe gripping portions 120 and 135 of the anchor device 100 releasablyengage with the outer surface of the catheter 20. In such embodiments,the anchor device 100 can be secured to the patient without the retainerbody 111 penetrating though the skin 30 of the patient and withoutnecessarily requiring sutures or adhesive tapes bonded to the skin 30.As previously described in connection with FIGS. 2-3, the cap assembly130 can be moved toward the base 110 (e.g., in the direction depicted byarrow 106) to close the anchor device 100 around the portion of thecatheter that is external to the skin 30. When in this closedconfiguration, the cap assembly 130 and base 110 can apply a compressiveforce from the gripping members 120 and 135 to the catheter 20, therebyapplying a frictional holding force to the catheter 20 or medicalinstrument therein.

The method may further include the step of anchoring the catheter 20 tothe skin penetration point 32 using the anchor device 100 duringdelivery of treatment through the catheter 20. For example, as shown inFIG. 1, the anchor device 100 can releasably anchor the catheter 20 tothe skin penetration point 32 while the catheter 20 resides in aselected blood vessel 40 to deliver a particular treatment (e.g., todeliver a fluid, to extract a fluid, to deliver an instrument orimplant, or the like). As shown in FIG. 1, the subcutaneous tines 145a-b serve to secure the anchor device 100 (and the catheter 20 securedthereto) to the skin penetration point 32 by abutting against anunderside of the skin 30.

The method may also include steps for removing the anchor device 100.During removal, the anchor device 100 can be adjusted to the foldedcondition once again so as to facilitate a prompt removal of thesubcutaneous tines 145 a-b from the skin penetration point. Accordingly,the removal process will be substantially the opposite order of steps asshown in FIGS. 4-7. For example, during removal, the cap assembly 130can be detached from the base 110 so that the catheter 20 can be freedfrom the base. The catheter 20 may be withdrawn from the skinpenetration point before the subcutaneous tines 145 a-b are removed, oralternatively, the catheter 20 may remain in place while thesubcutaneous tines 145 a-b are removed first. After the base 100 is freefrom the cap assembly 130 (in a condition similar to that of FIG. 6),the base can be adjusted to the same folded condition employed duringthe insertion technique (refer to FIG. 5). In such circumstances, thesubcutaneous tines 145 a-b are generally adjacent to each other andoriented to extend in substantially the same direction. As such, thesubcutaneous tines 145 a-b can be simultaneously removed while beingmaintained in a non-stressed configuration (refer to FIG. 4). Such aremoval process can be used to reduce the cross sectional area of theportion of the anchors 140 a-b being withdrawn through the skinpenetration point 32, thereby reducing the likelihood of damaging thesurrounding skin tissue 30 during removal of the anchors 140-b.

Accordingly, the anchor device 100 may have a foldable configurationthat facilitates both installation and removal of the subcutaneousanchors 140 a-b in a manner that reduces trauma to surrounding tissuenear the skin penetration point 32.

Referring now to FIGS. 8-9, some embodiments of the anchor device 100may include one or more structures that releasably retain the base 110of the anchor device 100 in the folded condition. For example, theanchor device 100 may be provided in a sterile package while beingretained in the folded condition. In such circumstances, a user canreadily remove the device 100 and begin to insert the subcutaneous tines145 a-b through the skin penetration point 132 (as shown in FIGS. 4-5)without having to manually adjust the base 110 to the folded condition.After insertion the subcutaneous tines 145 a-b into the subcutaneouslayer 32, the user can then remove or separate the one or morestructures that releasably retain the base 110 of the anchor device 100in the folded condition. The anchor device 100 can be biased toward thenon-folded condition (as shown in FIG. 6) upon removal of the one ormore structures.

As shown in FIG. 8, the some embodiments of the anchor device 100 mayinclude one or more removable structures that releasably retain the base110 of the anchor device 100 in the folded condition. For example, theremovable structure may include a U-shaped clip device 160 that slidablyengages the base 100. The U-shaped clip device 160 can be readilyremoved from the base 110 by sliding the clip device 160 in a lateraldirection generally perpendicular to the fold line 113 of the anchordevice 100. In a second example, the removable structure may include adifferent U-shaped clip device 170 that slidably engages the base 100from a longitudinal direction. The U-shaped clip device 170 can bereadily removed from the base 110 by sliding the clip device 160 in alongitudinal direction that is generally parallel to the fold line 113of the anchor device 100.

As shown in FIG. 9, the some embodiments of the anchor device 100 mayinclude one or more structures that are integrally formed with anothercomponent of the anchor device 100 so as to releasably retain the base110 of the anchor device 100 in the folded condition. For example, thestructure may include a snap-fit connector having mating components 180a-b that secure together when the base 110 is in the folded condition.The snap-fit connector components 180 a-b may include a mating tongue orextension that mates with a groove or detent. When the user is ready toadjust the anchor device 100 to the non-folded condition, the snap-fitconnector components 180 a-b can be manually separated by application ofa low separation force from the user. The U-shaped clip device 160 canbe readily removed from the base 110 by sliding the clip device 160 in alateral direction generally perpendicular to the fold line 113 of theanchor device 100.

In these embodiments illustrated in FIGS. 8-9, the anchor device 100 maybe provided in a sterile package while being retained in the foldedcondition by one or more of the clip device 160 or 170 or the snap-fitconnector components 180 a-b. From there, a user can readily remove thedevice 100 and begin to insert the subcutaneous tines 145 a-b throughthe skin penetration point 132 without being required to manually adjustthe base 110 to the folded condition.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the scope of the invention. Accordingly,other embodiments are within the scope of the following claims.

1. (canceled)
 2. An anchor device for releasably securing to an externalportion of a medical instrument while another portion of the medicalinstrument occupies a skin penetration point, the anchor devicecomprising: first and second anchors each having a longitudinal shaftportion and a subcutaneous tine configured to be deployed through theskin penetration point and into a subcutaneous region along an undersideof a skin layer; and a retainer base to releasably secure with theexternal portion of the medical instrument, the retainer base being in afolded condition about a longitudinal fold axis of the retainer baseprior to deployment of the subcutaneous tines through the skinpenetration point such that the subcutaneous tines are positionedgenerally adjacent to each other and oriented to extend in substantiallythe same direction, wherein the retainer base is adjustable to anon-folded condition about the longitudinal fold axis of the retainerbase after deployment of the subcutaneous tines through the skinpenetration point so that the subcutaneous tines are in an anchoredposition
 3. The device of claim 2, further comprising a mechanism thatreleasably retains the retainer base in the folded condition, whereinthe retainer base is biased to return to the non-folded condition. 4.The device of claim 3, the retainer base is adjustable to a non-foldedcondition about the longitudinal fold axis of the retainer base inresponse to releasing the mechanism from the retainer base so thatretainer base is urged to the non-folded condition by a spring biasforce.
 5. The device of claim 2, the retainer base includes a first bodyportion that is pivotably coupled to a second body portion about thelongitudinal fold axis of the retainer base, the longitudinal fold axisof the retainer base being defined by an elastically flexiblelongitudinal folding region positioned between the first body portionand the second body portion.
 6. The device of claim 5, wherein thelongitudinal shaft portion of each of the first and second anchorshaving a distal end portion that is coupled with a respective one of thesubcutaneous tines, the longitudinal shaft portion of the first anchorbeing mechanically coupled to the first body portion of the retainerbase, and the longitudinal shaft portion of the second anchor beingmechanically coupled to the second body portion of the retainer base. 7.The device of claim 5, further comprising a cap that is releasablyattachable to the retainer base so as to define a channel therebetweenthat is sized to retain the external portion of the medical instrument.8. The device of claim 7, wherein the retainer base and the cap eachinclude a gripper member configured to frictionally engage the externalportion of the medical instrument.
 9. The device of claim 7, wherein thecap includes: a first mounting structure to releasably attach to a firstmating structure of the first body portion of the retainer base, and asecond mounting structure to releasably attach to a second matingstructure of the second body portion of the retainer base, the first andsecond mating structures being positioned on opposite sides of thelongitudinal fold axis of the retainer base.
 10. The device of claim 2,wherein each of the subcutaneous tines has longitudinal convexly curvedportion extending toward a tip at a free end, the longitudinal convexlycurved portion being configured to abut against the underside of theskin layer.
 11. The device of claim 10, wherein each of the tips at thefree ends is rounded or other non-sharp so as to protect the undersideof the skin layer.
 12. The device of claim 2, wherein during theretainer base is in the folded condition about the longitudinal foldaxis of the retainer base prior to deployment of the subcutaneous tinesthrough the skin penetration point such that the subcutaneous tines arearranged in a side-by-side position so that tips of the subcutaneoustines are simultaneously insertable through the skin penetration pointwhile the skin penetration point is already occupied by the catheter.13. The device of claim 2, wherein the subcutaneous tines are configuredto be deployed through the skin penetration point while in a generallynon-stressed and non-flexed shape.
 14. The device of claim 13, whereinthe subcutaneous tines are configured to have the same generallynon-stressed and non-flexed shape after the subcutaneous tines areadjusted to the anchored position in the subcutaneous region.
 15. Thedevice of claim 2, wherein the medical instrument comprises a catheter.16. The device of claim 2, wherein the subcutaneous tines compriseflexible subcutaneous tines.
 17. The device of claim 2, wherein thelongitudinal shaft portion of the first anchor is positioned on anopposite side of the longitudinal fold axis from the longitudinal shaftportion of the second anchor, and wherein the longitudinal shaft portionof each of the first and second anchors extends distally in alongitudinal direction from a distalmost end of the retainer base. 18.The device of claim 2, wherein in the anchored position the subcutaneoustines extend generally away from one another.